Fire-resistant organic fibrous materials containing ethylene diamine di-hydrobromide



Patented Mar. 15, 1949 GFFKE FIRE-RESISTANT ORGANIC FIBROUS MA- TERIALS CONTAINING ETHYLENE DI- AMINE DI-HYDROBROMIDE Alexander James Wesson and Henry Charles Olpin, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application June 5, 1946, Serial No. 674,644. In Great Britain June 29, 1945 Claims. 1

This invention relates to the treatment of organic fibrous material of an organic substance, and in particular to a treatment designed to improve the resistance to fire of such materials.

We have found that the fire-resistance of fibrous materials having a basis of cellulose acetate or other organic fibre-forming substance can be very substantially increased by the application to the material of hydrohalide salts of aliphatic polyamines (including cliamines) and especially di-hydrobromide of ethylene diamine. This salt is substantially neutral to litmus and can be rendered quite neutral by the addition of a. small excess of the diamine.

The salts employed are water-soluble and the fire-proofing treatment of the invention can be very simply carried out by applying an aqueous solution of the salt to the material, removing excess of solution and drying. The treatment of the invention can usefully be applied, for example, to rugs, heavy curtains (such as are not normally laundered), upholstery-fabrics, mattress-ticking and filling, eiderdown covers and filling, and theatre furnishings, and in general to textile and other fibrous materials where fastness to washing is not required.

The invention may be illustrated as follows:

A cellulose acetate furnishing fabric is padded with a aqueous solution of a salt prepared by adding hydrobromic acid to ethylene diamine until the solution turns blue litmus faintly red. The padding mangle is adjusted so that 150% of solution based on the weight of the material is retained therein. The fabric is then dried. When the so treated fabric is exposed, together with two identical samples of fabric impregnated with the same weight of ammonium bromide and ammonium sulphamate respectively, to a naked flame, the last mentioned samples catch fire and burn for a short time, but the first mentioned sample does not catch fire at all. This shows that a high degree of fire-resistance has been imparted by the treatment with ethylene diamine hydrobromide. Samples of the same fabric impregnated with ethylene diamine, when subjected to the same test catch fire and burn vigorously.

Fabrics of cotton and of regenerated cellulose artificial silk, padded with the solution of ethylene diamine di-hydrobromide and dried while containing 100% of said solution are also found to be very effectively fireproofed.

Instead of the ethylene diamine hydrobromide, hydrobromides of polyalkylene polyamines can be used, for example those of diethylene triamine or tetraethylene pentamlne. These polyamines have the formula NH2.[C2H4NH]1LC2H4NH2. The dihydrobromides used may be made by neutralising the polyamine with hydrobromic acid, or by reacting it with one molecular proportion of the acid for each nitrogen atom. The salts obtained by the latter method impart higher fire-resistance but are objectionable for some purposes on account of their acid reaction. The invention includes also the use of the hydrochlorides corresponding to these various hydrobromides.

We have not found any of the polyamine hydrohalides as effective as ethylene diamine dihydrobromide. The fireproofing effect of the salts of the invention is the more remarkable since the corresponding free bases are found actually to promote burning of cellulose acetate, cotton and regenerated cellulose fabrics.

The fireproofing treatment of the invention can be applied to a variety of organic fibrous materials other than those specified above. Among such materials are textile materials of other carboxylic acid esters of cellulose, for example cellulose propionate, cellulose butyrate, cellulose acetatebutyrate, and cellulose acetate-stearate; of ethers of cellulose, for example ethyl cellulose, propyl cellulose and benzyl cellulose and ether-esters of cellulose, for example ethyl cellulose acetate; of fibrous polymers of olefinic compounds, for examle polyethylene and copolymers of vinyl acetate and vinyl chloride; and of fibrous condensationpolymers of bifunctional amines with bifunctional carboxylic acids, for example polyhexamethylene adipamide. The treatment may also be applied to natural fibres besides cotton, for example linen, silk, wool and hair; and to proteinaceous artificial fibrous materials, for example of casein or of soya bean protein. The textile materials can be treated in any convenient form, for example in the form of loose fibres, rovings, in yarn form, or in the form of fabrics.

Although the invention is of greatest utility in connection with textile materials, it can also be applied with some improvement in fire resistance to other fibrous materials, e. g. sheet materials such as papers, containing an organic fibre-forming substance, for example any of the fibreforming substances referred to above. In the production of papers of improved fire resistance the hydrobromide may be applied at any suitable stage in the manufacture.

Having described our invention, what we desire to secure by Letters Patent is:

1. Fibrous materials comprising an organic substance, said materials being of improved fire- 5. Fibrous materials comprising regenerated 5 4 cellulose, said materials being of improved fireresistance owing to a content of ethylene diamine di-hydrobromide.

ALEXANDER JAMES WESSON. HENRY CHARLES OLPIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,032,605 Whitehead Mar. 3, 1936 2,286,726 Gordon June 16, 1942 

